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Slide 1 :
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3G Tutorial Brough Turner & Marc Orange Originally presented at Fall VON 2002 |
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Slide 2 :
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Preface... The authors would like to acknowledgement material contributions from:
Murtaza Amiji, NMS Communications
Samuel S. May, Senior Research Analyst, US Bancorp Piper Jaffray
Others as noted on specific slides
We intend ongoing improvements to this tutorial and solicit your comments at:
rbt@nmss.com
and/or marc_orange@nmss.com
For the latest version go to:
http://www.nmscommunications.com/3Gtutorial |
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Slide 3 :
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Outline History and evolution of mobile radio
Brief history of cellular wireless telephony
Radio technology today: TDMA, CDMA
Demographics and market trends today
3G vision, 3G migration paths
Evolving network architectures
Based on GSM-MAP or on IS-41 today
3GPP versus 3GPP2 evolution paths
3G utilization of softswitches, VoIP and SIP
Potential for convergence |
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Slide 4 :
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Slide 4 Outline (continued) Evolving services
SMS, EMS, MMS messaging
Location
Video and IP multimedia
Applications & application frameworks
Is there a Killer App?
Business models
What’s really happening? When? |
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Slide 5 :
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3G Tutorial History and Evolution of Mobile Radio
Evolving Network Architectures
Evolving Services
Applications
Business Models
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Slide 6 :
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First Mobile Radio Telephone 1924 Courtesy of Rich Howard |
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Slide 8 :
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Cellular Mobile Telephony Frequency modulation
Antenna diversity
Cellular concept
Bell Labs (1957 & 1960)
Frequency reuse
Typically every 7 cells
Handoff as caller moves
Modified CO switch
HLR, paging, handoffs
Sectors improve reuse
Every 3 cells possible |
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Slide 9 :
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First Generation Advanced Mobile Phone Service (AMPS)
US trials 1978; deployed in Japan (’79) & US (’83)
800 MHz band — two 20 MHz bands
TIA-553
Still widely used in US and many parts of the world
Nordic Mobile Telephony (NMT)
Sweden, Norway, Demark & Finland
Launched 1981; now largely retired
450 MHz; later at 900 MHz (NMT900)
Total Access Communications System (TACS)
British design; similar to AMPS; deployed 1985
Some TACS-900 systems still in use in Europe |
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Slide 10 :
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Second Generation — 2G Digital systems
Leverage technology to increase capacity
Speech compression; digital signal processing
Utilize/extend “Intelligent Network” concepts
Improve fraud prevention
Add new services
There are a wide diversity of 2G systems
IS-54/ IS-136 North American TDMA; PDC (Japan)
iDEN
DECT and PHS
IS-95 CDMA (cdmaOne)
GSM |
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Slide 11 :
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D-AMPS/ TDMA & PDC Speech coded as digital bit stream
Compression plus error protection bits
Aggressive compression limits voice quality
Time division multiple access (TDMA)
3 calls per radio channel using repeating time slices
Deployed 1993 (PDC 1994)
Development through 1980s; bakeoff 1987
IS-54 / IS-136 standards in US TIA
ATT Wireless & Cingular use IS-136 today
Plan to migrate to GSM and then to W-CDMA
PDC dominant cellular system in Japan today
NTT DoCoMo has largest PDC network |
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iDEN Used by Nextel
Motorola proprietary system
Time division multiple access technology
Based on GSM architecture
800 MHz private mobile radio (PMR) spectrum
Just below 800 MHz cellular band
Special protocol supports fast “Push-to-Talk”
Digital replacement for old PMR services
Nextel has highest APRU in US market due to “Direct Connect” push-to-talk service |
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DECT and PHS Also based on time division multiple access
Digital European Cordless Telephony
Focus on business use, i.e. wireless PBX
Very small cells; In building propagation issues
Wide bandwidth (32 kbps channels)
High-quality voice and/or ISDN data
Personal Handiphone Service
Similar performance (32 kbps channels)
Deployed across Japanese cities (high pop. density)
4 channel base station uses one ISDN BRI line
Base stations on top of phone booths
Legacy in Japan; new deployments in China today |
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North American CDMA (cdmaOne) Code Division Multiple Access
All users share same frequency band
Discussed in detail later as CDMA is basis for 3G
Qualcomm demo in 1989
Claimed improved capacity & simplified planning
First deployment in Hong Kong late 1994
Major success in Korea (1M subs by 1996)
Used by Verizon and Sprint in US
Simplest 3G migration story today |
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cdmaOne — IS-95 TIA standard IS-95 (ANSI-95) in 1993
IS-95 deployed in the 800 MHz cellular band
J-STD-08 variant deployed in 1900 MHz US “PCS” band
Evolution fixes bugs and adds data
IS-95A provides data rates up to 14.4 kbps
IS-95B provides rates up to 64 kbps (2.5G)
Both A and B are compatible with J-STD-08
All variants designed for TIA IS-41 core networks (ANSI 41) |
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Slide 16 :
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GSM « Groupe Special Mobile », later changed to « Global System for Mobile »
Joint European effort beginning in 1982
Focus on seamless roaming across Europe
Services launched 1991
Time division multiple access (8 users per 200KHz)
900 MHz band; later extended to 1800MHz
Added 1900 MHz (US PCS bands)
GSM is dominant world standard today
Well defined interfaces; many competitors
Network effect (Metcalfe’s law) took hold in late 1990s
Tri-band GSM phone can roam the world today |
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Distribution of GSM Subscribers GSM is used by 70% of subscribers worldwide
564 M subs / 800 M subs in July 2001
Most GSM deployments in Europe (59%) and Asia (33%)
ATT & Cingular deploying GSM in US today Source: EMC World Cellular / GSM Association |
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Slide 18 :
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1G — Separate Frequencies |
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Slide 19 :
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2G — TDMA Time Division Multiple Access |
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Slide 20 :
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2G & 3G — CDMA Code Division Multiple Access Spread spectrum modulation
Originally developed for the military
Resists jamming and many kinds of interference
Coded modulation hidden from those w/o the code
All users share same (large) block of spectrum
One for one frequency reuse
Soft handoffs possible
Almost all accepted 3G radio standards are based on CDMA
CDMA2000, W-CDMA and TD-SCDMA |
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Slide 21 :
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Multi-Access Radio Techniques Courtesy of Petri Possi, UMTS World |
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Slide 22 :
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Courtesy of Suresh Goyal & Rich Howard |
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Slide 23 :
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Courtesy of Suresh Goyal & Rich Howard |
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Slide 24 :
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Courtesy of Suresh Goyal & Rich Howard |
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Slide 25 :
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Courtesy of Suresh Goyal & Rich Howard |
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Slide 26 :
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3G Vision Universal global roaming
Multimedia (voice, data & video)
Increased data rates
384 kbps while moving
2 Mbps when stationary at specific locations
Increased capacity (more spectrally efficient)
IP architecture
Problems
No killer application for wireless data as yet
Vendor-driven |
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Slide 27 :
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International Standardization ITU (International Telecommunication Union)
Radio standards and spectrum
IMT-2000
ITU’s umbrella name for 3G which stands for International Mobile Telecommunications 2000
National and regional standards bodies are collaborating in 3G partnership projects
ARIB, TIA, TTA, TTC, CWTS. T1, ETSI - refer to reference slides at the end for names and links
3G Partnership Projects (3GPP & 3GPP2)
Focused on evolution of access and core networks |
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IMT-2000 Vision Includes LAN, WAN and Satellite Services |
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Slide 29 :
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IMT-2000 Radio Standards IMT-SC* Single Carrier (UWC-136): EDGE
GSM evolution (TDMA); 200 KHz channels; sometimes called “2.75G”
IMT-MC* Multi Carrier CDMA: CDMA2000
Evolution of IS-95 CDMA, i.e. cdmaOne
IMT-DS* Direct Spread CDMA: W-CDMA
New from 3GPP; UTRAN FDD
IMT-TC** Time Code CDMA
New from 3GPP; UTRAN TDD
New from China; TD-SCDMA
IMT-FT** FDMA/TDMA (DECT legacy) * Paired spectrum; ** Unpaired spectrum |
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CDMA2000 Pros and Cons Evolution from original Qualcomm CDMA
Now known as cdmaOne or IS-95
Better migration story from 2G to 3G
cdmaOne operators don’t need additional spectrum
1xEVD0 promises higher data rates than UMTS, i.e. W-CDMA
Better spectral efficiency than W-CDMA(?)
Arguable (and argued!)
CDMA2000 core network less mature
cmdaOne interfaces were vendor-specific
Hopefully CDMA2000 vendors will comply w/ 3GPP2 |
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W-CDMA (UMTS) Pros and Cons Wideband CDMA
Standard for Universal Mobile Telephone Service (UMTS)
Committed standard for Europe and likely migration path for other GSM operators
Leverages GSM’s dominant position
Requires substantial new spectrum
5 MHz each way (symmetric)
Legally mandated in Europe and elsewhere
Sales of new spectrum completed in Europe
At prices that now seem exorbitant |
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TD-SCDMA Time division duplex (TDD)
Chinese development
Will be deployed in China
Good match for asymmetrical traffic!
Single spectral band (1.6 MHz) possible
Costs relatively low
Handset smaller and may cost less
Power consumption lower
TDD has the highest spectrum efficiency
Power amplifiers must be very linear
Relatively hard to meet specifications |
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Slide 33 :
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Migration To 3G |
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Slide 34 :
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Source: U.S. Bancorp Piper Jaffray Subscribers: GSM vs CDMA Cost of moving from GSM to cdmaOne overrides the benefit of the CDMA migration path |
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Slide 35 :
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Mobile Wireless Spectrum |
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Slide 36 :
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Prospects for Global Roaming Multiple vocoders (AMR, EVRC, SMV,…)
Six or more spectral bands
800, 900, 1800, 1900, 2100, 2500, …? MHz
At least four modulation variants
GSM (TDMA), W-CDMA, CDMA2000, TD-SCMDA
The handset approach
Advanced silicon
Software defined radio
Improved batteries
Two cycles of Moore’s law? i.e. 3 yrs? |
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Slide 37 :
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3G Tutorial History and Evolution of Mobile Radio
Evolving Network Architectures
Evolving Services
Applications
Business Models
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Slide 38 :
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Evolving CN Architectures Two widely deployed architectures today
GSM-MAP — used by GSM operators
“Mobile Application Part” defines extra (SS7-based) signaling for mobility, authentication, etc.
ANSI-41 MAP — used with AMPS, TDMA & cdmaOne
TIA (ANSI) standard for “cellular radio telecommunications inter-system operation”
Each evolving to common “all IP” vision
“All IP” still being defined — many years away
GAIT (GSM ANSI Interoperability Team) provides a path for interoperation today |
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BTS — Base Transceiver Station
BSC — Base Station Controller Typical 2G Architecture MSC — Mobile Switching Center
VLR — Visitor Location Register
HLR — Home Location Register |
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MSC HLR Network Planes Like PSTN, 2G mobile networks have one plane for voice circuits and another plane for signaling
Some elements reside only in the signaling plane
HLR, VLR, SMS Center, … MSC VLR Transport Plane (Voice) Signaling Plane (SS7) MSC SMS-SC |
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Signaling in Core Network Based on SS7
ISUP and specific Application Parts
GSM MAP and ANSI-41 services
Mobility, call-handling, O&M
Authentication, supplementary services
SMS, …
Location registers for mobility management
HLR: home location register has permanent data
VLR: visitor location register keeps local copy for roamers |
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Slide 42 :
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PSTN-to-Mobile Call (STP) (SCP) PSTN PLMN (SSP) (SSP) BSS MS PLMN (Home) (Visitor) (STP) HLR GMSC (SSP) VMSC VLR SCP |
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Slide 43 :
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BSS — Base Station System
BTS — Base Transceiver Station
BSC — Base Station Controller
MS — Mobile Station NSS — Network Sub-System
MSC — Mobile-service Switching Controller
VLR — Visitor Location Register
HLR — Home Location Register
AuC — Authentication Server
GMSC — Gateway MSC GSM 2G Architecture GSM — Global System for Mobile communication |
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Enhancing GSM New technology since mid-90s
Global standard — most widely deployed
significant payback for enhancements
Frequency hopping
Overcome fading
Synchronization between cells
DFCA: dynamic frequency and channel assignment
Allocate radio resources to minimize interference
Also used to determine mobile’s location
TFO — Tandem Free Operation |
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TFO Concepts Improve voice quality by disabling unneeded transcoders during mobile-to-mobile calls
Operate with existing networks (BSCs, MSCs)
New TRAU negotiates TFO in-band after call setup
TFO frames use LSBits of 64 Kbps circuit to carry compressed speech frames and TFO signaling
MSBits still carry normal G.711 speech samples
Limitations
Same speech codec in each handset
Digital transparency in core network (EC off!)
TFO disabled upon cell handover, call transfer, in-band DTMF, announcements or conferencing |
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Slide 46 :
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TFO – Tandem Free Operation No TFO : 2 unneeded transcoders in path
With TFO (established) : no in-path transcoder A BTS BSC Ater MSC MSC BSC MS MS BTS Abis GSM Coding G.711 / 64 kb GSM Coding CD DC CD DC (**) or 7 bits if Half-Rate coder is used A BTS BSC Ater MSC MSC BSC MS MS BTS Abis GSM Coding [GSM Coding + TFO Sig] (2bits) + G.711 (6bits**) / 64 Kb GSM Coding CD TFO TFO DC PSTN* PSTN* (*) or TDM-based core network |
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New Vocoders: AMR & SMV AMR: Adaptive multi-rate
Defined for UMTS (W-CDMA)
Being retrofitted for GSM
SMV: Selectable mode vocoder
Defined by 3GPP2 for CDMA2000
Many available coding rates
AMR 8 rates: 12.2, 10.2, 7.95, 7.4, 6.7, 5.9, 5.15 & 4.75bps, plus silence frames (near 0 bps)
SMV 4 rates: 8.5, 4, 2 & 0.8kbps
Lower bit rates allow more error correction
Dynamically adjust to radio interference conditions |
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Slide 48 :
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Enhancing GSM AMR speech coder
Trade off speech and error correction bits
Fewer dropped calls
DTX — discontinuous transmission
Less interference (approach 0 bps during silences)
More calls per cell
Overlays, with partitioned spectral reuse
3x in overlay (cell edges); 1x reuse in underlay
HSCSD — high speed circuit-switched data
Aggregate channels to surpass 9.6 kbps limit (?50k)
GPRS — general packet radio service |
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GPRS — 2.5G for GSM General packet radio service
First introduction of packet technology
Aggregate radio channels
Support higher data rates (115 kbps)
Subject to channel availability
Share aggregate channels among multiple users
All new IP-based data infrastructure
No changes to voice network |
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2.5G / 3G Adds IP Data No Changes for Voice Calls |
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Slide 51 :
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BSS — Base Station System
BTS — Base Transceiver Station
BSC — Base Station Controller NSS — Network Sub-System
MSC — Mobile-service Switching Controller
VLR — Visitor Location Register
HLR — Home Location Register
AuC — Authentication Server
GMSC — Gateway MSC 2.5G Architectural Detail SGSN — Serving GPRS Support Node
GGSN — Gateway GPRS Support Node GPRS — General Packet Radio Service 2G MS (voice only) |
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GSM Evolution for Data Access 1997 2000 2003 2003+ GSM GPRS EDGE UMTS 9.6 kbps 115 kbps 384 kbps 2 Mbps GSM evolution 3G |
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EDGE Enhanced Data rates for Global Evolution
Increased data rates with GSM compatibility
Still 200 KHz bands; still TDMA
8-PSK modulation: 3 bits/symbol give 3X data rate
Shorter range (more sensitive to noise/interference)
GAIT — GSM/ANSI-136 interoperability team
Allows IS-136 TDMA operators to migrate to EDGE
New GSM/ EDGE radios but evolved ANSI-41 core network
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3G Partnership Project (3GPP) 3GPP defining migration from GSM to UMTS (W-CDMA)
Core network evolves from GSM-only to support GSM, GPRS and new W-CDMA facilities
3GPP Release 99
Adds 3G radios
3GPP Release 4
Adds softswitch/ voice gateways and packet core
3GPP Release 5
First IP Multimedia Services (IMS) w/ SIP & QoS
3GPP Release 6
“All IP” network; contents of r6 still being defined |
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Slide 55 :
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3G rel99 Architecture (UMTS) — 3G Radios SS7 IP BTS BSC MSC VLR HLR AuC GMSC BSS SGSN GGSN PSTN PSDN CN Gs BSS — Base Station System
BTS — Base Transceiver Station
BSC — Base Station Controller
RNS — Radio Network System
RNC — Radio Network Controller CN — Core Network
MSC — Mobile-service Switching Controller
VLR — Visitor Location Register
HLR — Home Location Register
AuC — Authentication Server
GMSC — Gateway MSC SGSN — Serving GPRS Support Node
GGSN — Gateway GPRS Support Node A E PSTN 2G MS (voice only) 2G+ MS (voice & data) UMTS — Universal Mobile Telecommunication System Gb |
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3G rel4 Architecture (UMTS) — Soft Switching |
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Slide 57 :
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Transcoder Free Operation (TrFO) Improve voice quality by avoiding unneeded transcoders
like TFO but using packet-based core network
Out-of-band negociation
Select same codec at both ends during call setup
Supports sudden channel rearrangement (handovers, etc.) via signaling procedures
When TrFO impossible, TFO can be attempted
e.g. transit between packet-based and circuit-based core networks
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Slide 58 :
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TrFO + TFO Example 2G handset to 3G handset: by combining TrFO and TFO, in-path transcoders can be avoided 3G Packet
Core Network 3G UE Radio Access Network 2G PLMN MSC Server CS-MGW CS-MGW GMSC Server MSC GSM Coding (TrFO) GSM Coding CD DC TFO [GSM Coding + TFO Sig] (lsb)
+ G.711 (msb) / 64 Kb TFO Radio Access Network 2G MS |
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Slide 59 :
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3G rel5 Architecture (UMTS) — IP Multimedia |
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